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ESOS Phase 4 compliance

Who qualifies.What is audited.What is filed.

ESOS Phase 4

A clear route from scope to submission.

ESOS brings company structure, financial tests and energy records into one assessment. We organise that evidence so each conclusion can be checked.

Plant room pipework and energy equipment examined during an energy survey
Survey evidenceBuildings, transport and industrial processes are brought into the same audit trail.
01Scope gate

Start with the organisation, not the meter.

We test each UK entity against the qualification rules, then map how the group rule affects the rest. The answer is set out in writing before the energy assessment begins.

Read the full Phase 4 guide
Entity testCheck each UK undertaking
Group ruleMap connected UK entities
Written outcomeIn scope or outside scope
Compliance documents reviewed as part of an energy assessment
Evidence registerEvery source is named, dated and connected to the calculation that uses it.
02Evidence

One traceable record.

The assessment is only as dependable as its source material. We assemble the records needed to show what was included, where it came from and how it was treated.

  1. 01

    Corporate group structure and each UK entity

  2. 02

    Headcount, turnover and balance sheet position

  3. 03

    Building, transport and process energy use

  4. 04

    Meter data, AMR records and invoices

  5. 05

    Previous action plans, measures implemented and savings achieved

03Assessment

Keep today’s requirements separate from what may change.

We confirm the position against current guidance when we review your organisation. Proposed changes stay visibly labelled until they become law.

Current Phase 4 position

Qualification, assessment and filing

  • Qualification is assessed afresh for the phase.
  • The corporate group rule must be considered.
  • Energy use must be measured and significant consumption assessed.
  • The appropriate lead assessor route must be followed.
  • An action plan, progress reporting and notification are required.

Now in force

The 2026 rules are law.

The amending regulations came into force on 22 July 2026 and the Environment Agency has published its Phase 4 guidance. Assessments must now report progress against the last action plan and explain anything not implemented. We confirm the current position against that guidance when we review your organisation.

04Action plan

The filing is the end of the compliance task, not the end of the work.

The useful output is a written set of actions your team can examine, prioritise and progress. We show the evidence and calculations behind each recommendation.

  1. 01

    A written scope determination for each UK entity

  2. 02

    Energy measurement with every source identified

  3. 03

    An audit and quantified opportunities where figures can be established

  4. 04

    The action plan and progress report

  5. 05

    The compliance notification and filing record

Questions

Who has to comply with ESOS?
A large undertaking, tested at 250 or more UK employees on its own, or turnover above £44m together with a balance sheet total above £38m. Your position on the qualification date of 31 December 2026 decides whether you are in scope for Phase 4.
What is the ESOS Phase 4 deadline?
5 December 2027. The compliance notification must reach the Environment Agency, or the devolved nation equivalent, by then, through MESOS.
We qualified for Phase 3. What is due now?
Your final Phase 3 progress update is due by 5 December 2026, signed off by a board level director and submitted through MESOS. It needs the savings data and implementation evidence that Phase 4 will ask for again.
We did not qualify last time. Are we safe?
No. Qualification is assessed afresh each phase, so not qualifying before does not carry forward. An organisation that missed the Phase 3 snapshot on 31 December 2022 may qualify now after four years of growth.
Does one subsidiary bring the whole group in?
Yes. If any single UK entity in a corporate group meets the test, every UK entity in that group is brought into scope, including ones individually well below the threshold. This is the point most often missed.
Is ESOS the same test as SECR?
No. ESOS is 250 or more employees on its own, or both financial thresholds together. SECR is two of three thresholds. The same company can sit inside one regime and outside the other, so both need checking on your actual figures.
What does ESOS support cost?
The initial review, which establishes whether you are in scope and what data you hold, costs nothing. The assessment work itself is quoted and agreed in writing before it starts, and the lead assessor requirement is set out in that quotation.

Read the detail

Related: SECR reporting, all compliance work and commercial energy audits.

How to check this

Each claim on this page is answered by something you can read for yourself. Nothing below states a figure; it names the document or register the claim is held against.

  • Point 01

    We hold a Level 1 Letter of Authority only

    The authority wording sets out what we may do with your data and states that we cannot sign a contract on your behalf. Read it before you sign it.

    Read the Letter of Authority

  • Point 02

    How we are paid is agreed in writing before you sign

    Our margin or management fee is stated in the terms that accompany a recommendation, and nothing is added afterwards.

    Client terms and conditions

  • Point 03

    Every figure we quote carries a dated source document

    Records state the figure, what it is measured against, the document it is taken from and the date on that document. Records still held anonymous are labelled as such.

    Evidence records

  • Point 04

    Compliance work is held against the current legislation

    Each obligation is recorded with the rule it comes from and the deadline it carries, in an evidence pack an auditor can follow.

    Compliance

  • Point 05

    We work to a published code of conduct

    Our obligations as a third party intermediary, and what you can hold us to, are set out in full.

    Third party intermediary code

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